The present invention relates to a method for the offline programming of an NC-controlled manipulator, an offline programming system, and a manipulator system.
NC-controlled manipulators are often used today as six-axis jointed-arm robots in automated production. Due to complex operating sequences, high demands are placed on users in regard to the programming of such manipulators.
To minimize the amount of time spent online for programming, the trend in many areas has been to shift as much programming as possible offline. In that case, the relevant NC program is created in such a manner that it is decoupled from the production line in terms of time and possibly in terms of space.
A known offline programming system for an NC-controlled manipulator provides a simulation in which trajectories can be simulated and programmed (EP 1 832 947 A2). Said offline programming system can also be used to simulate and program sensor-supported trajectories. A sensor assigned to the manipulator is modeled and simulated for this purpose. An NC program is then regularly created in a postprocessor, thereby transforming the simulated, virtual trajectories into real trajectories.
A problematic aspect of offline programming is that the real circumstances and the virtual circumstances are never fully identical. This relates to the occurrence of geometric deviations on the manipulator and on environmental components such as workpieces or the like. This also relates to control-related measures for axial compensation for offsetting changes in the manipulator kinematics caused by the environment.
The deviations mentioned initially can be corrected by the use of sensors. Said correction is always associated with a certain displacement of the tool center point (TCP) of the manipulator. The latter deviations are manifested as offsets in the axis values, however.
Both of the aforementioned deviations can cause the manipulator to enter into singularities in the working mode. In that case, the production line typically comes to a standstill and the trajectories must be re-taught. The costs incurred due to loss of production and restart thereof are usually considerable.